For almost 20 years high-T_c superconductors have been in the focus of condensed matter research. Despite all the effort, the mechanism leading to the transition temperatures as high as 160 K is still elusive. However significant experimental progress has been made, which can be instrumental in narrowing down the field of plausible microscopic scenarios of high-T_c superconductivity. The focus of the talk will be on some recent developments in the experimental studies of high-T_c cuprates using infrared and optical spectroscopy. In particular I will demonstrate how IR spectroscopy can be employed to monitor charge inhomogeneities, such as "stripes", in the cuprates.